The general aim of this project is to provide an understanding of aphasic syndromes in terms of the processing models that have emerged from contemporary work in psycholinquistics. Analysis of these disorders in terms of the disruption of components of normal language is expected to provide a principled basis for the remediation of these deficits, and to yield a functional architecture that can ultimately be mapped onto neural systems. Specific objectives for the next funding period include (1) Analysis of lexical, phonological and syntactic error patterns in aphasics with a view toward validation and extension of an interactive model of speech production.l Tests of the model will include computer simulation studies, in which the model will be 'lesioned' to generate the error patterns produced by individual patients. (2) Further analyses of particular impairments in sentence comprehension and production, continuing work begun in the present funding period. This work will include quantitative analyses of structural deficits in speech production, implementing procedures recently developed, with the goal of identifying factors underlying patient variation. (3) Applied studies, which include the development of theoretically-motivated treatment programs for 'syntactic' production and comprehension. (4) Studies in normal subjects to provide converging evidence for processing distinctions that have emerged from investigations of sentence processing in aphasics.